Dealing with any kind of "in-law" can be a pain, because they are close enough to be your family and distant enough for you to barely understand them. Here is a guide on how to deal reasonably with an argumentative sister-in-law.

Steps

1

Examine the situation closely. Are you misinterpreting the signals that she is sending out? Could you be overreacting? Ensure that the source of the problem is not you before jumping to conclusions.

2

Attempt to discern the source of conflict. Is she mad at you because she thinks that you do not deserve her sibling? Did you do something in the past that caused her to lose faith in you?

3

Work out the dispute in a mature fashion. Your sister-in-law may not like you at all, but you have a responsibility to resolve the conflict to avoid family drama. You do not have to prove yourself to your sister-in-law, but attempt to explain your motives and reasons for past actions. Show her that you are a responsible husband/wife to her sibling, and demonstrate care and compassion even when she embarrasses you in front of family.

4

If you cannot resolve the dispute, admit that you tried and move along. Explain to your wife/husband that his/her sister is treating you poorly, and attempt to get your spouse to talk with her.

5

Sometimes in life there are those that will not negotiate at all, even if you try to reach them at a reasonable level. One must vent, and not hold in pain, that has even been confirmed by professionals.